Answer this question truthfully
### Question: What to expect if I have Phenylketonuria  (Outlook/Prognosis)?
### Response: The outcome is expected to be very good if the diet is closely followed, starting shortly after the child's birth. If treatment is delayed or the condition remains untreated, brain damage will occur. School functioning may be mildly impaired.
If proteins containing phenylalanine are not avoided, PKU can lead to mental retardation by the end of the first year of life.